In general, color photographic images can be formed by color-developing an imagewise exposed light-sensitive material in a color developer containing an aromatic primary amine developing agent such as p-phenylenediamine, then subjecting it to the processing of bleaching, fixing, washing with water, and stabilizing. A bleach-fixing processing is also known, in which bleaching and fixing are conducted at the same time for accelerating the ordinary processing.
In recent years, it has been regarded important to keep the environment clean, and to save and recover water and silver in automatic processing color photographic materials in a continuous manner, and method for preventing environmental pollution, methods for effectively recovery silver, methods for reducing the amount of washing water, methods for re-using washing water, and the like have been eagerly demanded.
In view of simplifying photographic processing, too, it has been strongly desired to reduce the amount of replenishing developer in a replenishing type development processing step.
In continuous development processing, the replenishing amount of a developer used somewhat varies depending upon the kind of light-sensitive materials to be processed, but is usually about 1300 to 1100 ml per m.sup.2 of processed silver halide color photographic materials for photographing use.
From the above-described standpoint, it has been desired to reduce the amount of replenishing developer. However, reduction in amount of replenishing developer leads to deterioration of photographic properties, and hence it is generally extremely difficult.
On the other hand, in order to fill the demand for maintaining a clean environment, various processes have been tried for reproducing color developer in color development processing steps.
For example, there are illustrated those described in J. Appl. Phot. Eng., 5, 208 (1979), Gekkan Labo, 15, 113 (1979), SMPTE, J., 88, 165 (1979), J. Appl. Phot. Eng., 5, 32 (1979), SMPTE, J. 88, 168 (1979), Japanese Patent Application (OPI) Nos. 143018/77, 1462336/77, 149331/78, 9629/79, J. Appl. Phot. Eng., 5, 216 (1979), etc.
In general, reduction in the amount of replenishing developer results in a relative increase in the amount of substance dissolved into the developer from silver halide photographic materials (for example, halide ions produced by decomposition of silver halide), causing the problem of reduction in sensitivity.
As a countermeasure for this problem of reduction in sensitivity, it has been attempted to raise the processing temperature to reduce the amount of replenishing developer without reduction in sensitivity. For example, there is a color paper-processing agent made by Hunt Co. (processing agent CP-LR) (specially described in Photographic Bulletin, No. 49 (published by Hunt Co.), p. 6, in the item of "Color Print Chemistries"), and processes are described in "Preliminary Text for the Meeting of the Photographic Society of Japan, A-7", "Reduction in the amount of replenisher in color paper processing" (1980), etc. Additionally, the former processing agent enables reduction in the amount of replenishing color developer 1/2 to 2/3.
However, since these are agents for processing color papers, they cannot be applied as such to color photographic materials for photographing use in view of the problems with respect to photographic properties such as sensitivity, gradation, color reproduction, etc.
In processing color negative-working films, the aforesaid processing agent made by Hunt Co. (described in Photographic Bulletin, No. 55 published by Hunt Co.) has a formulation of replenishing in an amount as low as 754 ml per m.sup.2. However, it is still insufficient with respect to processing stability.
This may be attributed to the fact that, as a problem peculiar to color photographic materials for photographing use, a development inhibitor released after a coupling reaction from a DIR (development inhibitor-releasing) type coupler which is often used for improving interlayer effect and sharpness dissolves into and accumulates in the developer.
It is, therefore, a primary object of the present invention to provide a process for processing silver halide color photographic materials for photographing use without causing the problem with photographic properties such as desensitization in the case of reducing the amount of replenishing developer.
On the other hand, fundamental steps of color light-sensitive materials are generally a developing step and a silver-removing step. In the color-developing step, exposed silver halide is reduced with a color-developing agent to produce silver and, at the same time, the oxidized color-developing agent in turn reacts with a color former (coupler) to give a dye image. In the subsequent silver-removing step, silver having been produced in the color-developing step is oxidized by the action of an oxidant (called bleaching agent), then dissolved with a silver ion-chelating agent usually called a fixing agent. After this silver-removing step, only a dye image is formed in the color light-sensitive material.
The above-described silver-removing step is conducted in two manners: one being conducted using two baths of a bleaching agent-containing bleaching bath and a fixing agent-containing bath; and the other being conducted using a mono-bath of a bleach-fixing bath containing both a bleaching agent and a fixing agent.
In addition to the above-described fundamental steps, actual development processing involves various auxiliary steps such as a hardening bath, a stopping bath, an image-stabilizing bath, a water-washing bath, etc., for the purpose of keeping the photographic and physical quality of the image, or for impoving preservability of the image.
In general, red pressiate, dichromates, ferric chloride, ferric aminopolycarboxylate complex salts, persulfates, etc., are known as the bleaching agents.
However, red prussiate and dichromates involve the environmental pollution problem with respect to cyan compounds and hexavalent chromium, and require special processing equipment. Ferric chloride involves the problem of production of ferric hydroxide in the subsequent water-washing step and the problem of forming stains, thus involving various difficulties in practical use. Persulfates have the defect that they possess such a weak bleaching effect that they require a seriously long bleaching time. As to this defect, it has been proposed to enhance the bleaching effect by using together a bleaching accelerator. However, persulfates themselves are regulated by the law of the prevention and extinction of fire which provides persulfates and dangerous substances, and require various measures for storage, thus being generally difficult to use.
Ferric aminopolycarboxylate complex salts (particularly ferric ethylenediaminetetraacetate complex salts or ferric diethylenetriaminepentaacetate complex salts) are at present most widely used as bleaching agents since they cause less environmental problems and can be stored with no trouble which is different from persulfates. However, the bleaching power of the ferric aminopolycarboxylate complex salts is not necessarily sufficient. When they are used as bleaching agents, the desired purpose can be attained to some extent in the case of bleaching or bleach-fixing low speed silver halide color light-sensitive materials primarily containing a silver chlorobromide emulsion, but there results insufficient removal of silver, or a long bleaching time is required in the case of bleaching or bleach-fixing high speed color-sensitized color light-sensitized materials primarily containing a silver chlorobromoiodide or silver bromoiodide emulsion, particularly color reversal light-sensitive materials and color negative light-sensitive materials for photographing using high silver content emulsions.
For example, in bleach-fixing color negative-working light-sensitive materials for photographing use using a bleaching solution containing ferric aminopolycarboxylate complex salt, bleaching must be conducted for at least four minutes and, in order to keep the bleaching powder, complicated control such as control of pH of the bleaching solution and controlled aeration are required. In fact, such control still often fails to prevent bleaching failure.
Further, in order to remove silver, a processing using a fixing solution for at least 3 minutes is required subsequent to the bleaching processing. It has been eagerly desired to shorten the long time required for the silver-removing processing.
On the other hand, as a means for accelerating the silver-removing step, a bleach-fixing solution containing a ferric aminopolycarboxylate complex salt and a thiosulfate as described in German Pat. No. 866,605 is known. However, when allowed to be copresent with the thiosulfate having a reducing power, the ferric aminopolycarboxylate originally having a weak oxidizing (bleaching) powder undergoes such a serious reduction of bleaching power that it is extremely difficult to fully remove silver from a high-speed, high-silver content color light-sensitive material for photographing use, thus such means cannot be put into practice. Of course, various attempts have so far been made to remove the above-described effects of the bleach-fixing solution. For example, there is a technique of adding an iodide or bromide as described in British Pat. No. 926,569 and Japanese Patent Publication No. 11854/78 and a technique of incorporating a ferric aminopolycarboxylate complex salt in a high concentration with the aid of triethanolamine as described in Japanese Patent Application (OPI) Nos. 192953/82 and 95834/73 (the term "OPI" as used herein means an "unexamined published patent application") and U.S. Pat. No. 4,552,834. However, these techniques provide still insufficient effects, and cannot be practically employed with sufficient effects.
In addition to the problem of insufficient silver-removing power, the bleach-fixing solution involves a serious problem of spoiling color reproduction by reducing a cyan dye once formed by the color developement to a leuco dye. This problem is known to be solved by raising the pH of the bleach-fixing solution as is described in U.S. Pat. No. 3,773,510. However, a raised pH further weakens the bleaching power, and thus cannot be employed. U.S. Pat. No. 3,189,452 discloses a process of oxidizing, after the processing in the bleach-fixing solution, the leuco dye to the former cyan dye by using a bleaching solution containing red prussiate. However, the use of red prussiate involves the problem of environmental pollution as has been described hereinbefore and, even when bleaching is further conducted after the bleach-fixing processing, the amount of remaining silver is scarcely decreased.
As another technique for raising the bleaching power of ferric aminopolycarboxylate complex salt, it has been proposed to add various bleaching accelerators to a bleaching bath, a bleach-fixing bath, or a pre-bath thereof.
As the bleaching accelerators, there are illustrated, for example, various mercapto compounds as described in U.S. Pat. No. 3,893,858, British Pat. No. 1,138,842, and Japanese Patent Application (OPI) No. 141623/78, disulfide bond-containing compounds described in Japanese Patent Application (OPI) No. 98630/78, thiazolidine derivatives as described in Japanese Patent Publication No. 9854/78, isothiourea derivatives as described in Japanese Patent Application (OPI) No. 94927/78, thiourea derivatives as described in Japanese Patent Publication Nos. 8506/70 and 26586/74, thioamide compounds as described in Japanese Patent Application (OPI) No. 42349/74, dithiocarbamic acid salts as described in Japanese Patent Application (OPI) No. 26506/80, etc.
Some of these accelerators show a bleaching-acclerating effect to some extent, but the effect is not necessarily sufficient. Thus, they fail to meet the requirement for shortening the processing time.